If you do a search on this forum you will find all the information you need. It has all been discussed a million times before!
Just as a brief summary of what you will find: there are very few commercial sponsorships available. Those that currently exist include CTC-McAlpine's scheme for easyJet (and a couple of other airlines), flybe, and Air Atlantic. That's about it. There's plenty of info about all these here on this forum. Don't expect BA to restart its sponsorship scheme anytime soon. When it does restart, it is likely to be similar to the easyJet scheme.
The RAF (or Royal Navy) is quite a different kettle of fish. To succeed in the interview phase you will have to convince them that you want to fly for the military above all else. You won't go down well if you hint that your aim is to fly for BA and the RAF seemed like the cheapest way of getting a licence! Remember, the job of the military is to kill and to risk being killed. Think very carefully about that before you embark on this course. However, the training is the best available and the flying is incomparable - I did 22 years of it before I 'retired' to a B747!
Scroggs